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Old 09-18-2020, 12:35 PM   #261
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Quote:
Originally Posted by rvsprinterguy View Post
Can I ask for a summary of what you've built, its specs, and its cost?

Costs in US $
$378 for 135Ah LiFePO4 at 12.8V nominal
$235 for three 150A BMS boards (450A total)
$90 for my DIY 20A DC-DC charge controller
$60 copper buss (have some left)
$50 for three cases
$45 wire (have some left)
$20 for active balancer
$13 for terminals
then there's miscellaneous stuff like solder, kapton tape, bolts, nut, washers etc. (have some left)

I think these BMS boards are a great value and are what sets this apart from typical drop-in batteries. I have full access to 58 settings in the BMS plus an accurate state of charge meter all accessed through an app on my phone via Bluetooth connection. I can view pack temperature, state of cell balance, voltage, capacity remaining and even turn off discharging. I choose the high/low temperature & voltage setting and balancing voltage and precision etc. It's exactly what I wanted.

If the packs are connected in parallel the combined capacity is 135Ah. If discharged at 3C they could power a short duration 5,000 Watt load.

Pack 1: 58Ah 18 lbs
Pack 2: 58Ah 18 lbs
Pack 3: 19Ah 8 lbs

The DC-DC charge controller is also controlled by app on my phone through a Bluetooth connection. I really like that I can set both voltage and current. The latest app version lets me recall 9 different programed presets. The missing feature is automatic charge termination. I have to be within Bluetooth range to stop charging or I can set the voltage lower if away or just turn it off. I will try using macro apps on Android to automatically click the Off button after elapsed time. If that works then I'll try a more ambitious macro that recalls a preset based on elapsed time.

I have no defined use for these batteries and have various options. Each pack with an inverter could be placed in a different areas of the house during a power outage. I could place one or more packs in the van to supplement the AGM's.

I've learned so much during the entire process and that's basically priceless.
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Old 09-18-2020, 02:08 PM   #262
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Quote:
Originally Posted by markopolo View Post
I've learned so much during the entire process and that's basically priceless.

This boils it down to the, IMO, most important point of taking on projects like this. It is also, IMO, probably one of the most misunderstood points of taking on projects like this.


It doesn't matter if it is economically beneficial or even that it works well, or at all, if you learn a bunch of stuff in the process.



Adding to the community knowledge base is one of the best things that any of us can do.
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Old 09-18-2020, 02:37 PM   #263
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Thanks for the summary!

I've enjoyed reading about your project and was curious how it all turned out. Your recent post about mounting a solar panel on your cargo box in the back, which I think included a picture of one of your battery banks, is what triggered my question about your project's outcome.

Also, I've been looking at commercial Li-ion battery bank/power supplies such as those made by Goal Zero and Jackery, and wanted to get a comparison of specs.

I have to agree that the learning part is priceless!
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Old 09-18-2020, 03:49 PM   #264
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Just some updates:

The current version of the RuiDeng DPS app now lets you choose from 9 stored presets. You can have lithium and lead acid suitable profiles for example. Screenshots of the previous and current RuiDeng DPS apps:


Previous
RuiDeng DPS previous version.png
Current
RuiDeng DPS current version.png
-----------------------------

Diodes....... again!

I really like the idea of supplementing PbA batteries by adding LFP batteries in parallel. A DC/DC charge controller protects the input side of the LFP batteries. Adding a diode on the LFP output protects the LFP from unwanted charge sources like direct from alternator or extended solar controller and converter/charger float for example.

I have three 50A Ideal Diodes purchased on Amazon for $25 total. I'll experiment with them soon. I'll probably put them in parallel in small project box. Max load in the van would be 90A so two Ideal Diodes could do it but three should cover any unpredictability due to parallel operation.

My 15A & 50A Ideal Diodes:

ideal diode.JPG

There's very little voltage drop with Ideal Diodes. maybe 0.04V when the electronics kick in compared to 0.30V (0.2V to 0.4V) with Schottky diodes and 0.70V with silicon diodes.

Here's an Ideal Diode test I found on Youtube:


Info about Ideal Diodes from TI:


By using an Ideal Diode, I should be able to use much more of the LFP battery's capacity when paralleling LFP & PbA batteries before load sharing begins. Use the LFP with its thousands of cycles first.

I could always just turn off the LFP output side when not wanted but there's a chance I'd leave it on and drive off exposing the LFP battery to high current charging from the alternator.

I will still use the software switch to turn off the LFP output side as/when needed.

JBD BMS compatible Apps:

Liontron released a new app version. It's view only but once things are setup you mostly just want to view the current status of the battery. It works with my packs:


Liontron
new Liontron app 1.png
Liontron
new Liontron app 2.png

From Google Play Store:

Full access app: CarpLounge
View only: Liontron v1 & v2, Solmax/Solarfam, Polinovel & Xiaoxiang BMS all work with my packs.
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Old 10-03-2020, 01:12 PM   #265
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Another idea for modest LFP assisting an existing PbA battery coach:

parallel PbA LFP.jpg

The "Smart DC/DC" consists of:

1. Relay ($10-$20)
2. Voltage Comparator module ($15)
3. DC DC Constant Current 14.5V 22A boost/buck Battery Charger ($30-$50)
4. 30A programmable Charge Control module ($10)
5. Ideal Diode device (or similar)

The Comparator monitors systems voltage and closes the Relay if system voltage is between 13.6V & 14.8V.

The 30A programmable Charge Control module monitors the LFP battery and begins charging if 13V is breached. It turns off charging when 14.4V is reached. Charging effectively only happens when charge sources (alternator, generator, shore, solar) are on and the PbA side is at 13.6V or more.

The Ideal Diode prevents unwanted back-flow charging into the LFP battery.

All voltage settings are adjustable / programmable.

There would be a bit of a loop overlap going on sometimes but the LFP would drop out of the charging loop by just reaching 14.4V and the PbA would continue alone on its absorption cycle.

This setup cycles the LFP battery. The PbA side can be on float charge but LFP charging is only initiated when allowed by the 30A programmable Charge Control module.

DC-12V-24V-Car-Automotive-200A-High-Current-Emergency-Power-Start-Relay-1-8W-4-8W.jpg

DVB01-Digital-Led-Voltage-Comparator.jpg

XWST-DC-DC-Constant-Current-Battery-Charger-9-35V_14-5V.jpg

12V-6-60V-Battery-Charging-Protection-Module-LED-Display-Control-Module-Storage-Lithium-lead-aci.jpg
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Old 10-03-2020, 01:54 PM   #266
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Does the 30 amp control module do the current limiting from the lithium battery to lead acid one or does the battery charger?
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Old 10-03-2020, 02:28 PM   #267
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Current limiting is by the 22A charger. I wouldn't try to pass 30A through the 30A charge controller as I'm not 100% sure of its continuous capability (at 14VDC). If higher current is needed then a comparator + relay could be used.

The comparator has 5 functions to choose from:

1. voltmeter
2. charge controller
3. discharge controller
4. within voltage range
5. outside of voltage range
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Old 11-05-2020, 03:29 PM   #268
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Just some topic maintenance about the 150 amp JBD ( Jiabaida ) Smart BMS with Bluetooth wiring.

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Originally Posted by markopolo View Post
I discovered an anomaly of this BMS - https://www.classbforum.com/forums/f...tml#post103473 - and a better way to connect the balance wires (I think).

These boards typically have a JST type connector for the balance wires. The total amount of connector pins usually exceeds the number of batteries in series. This 4S BMS has a 5 pin JST connector and came supplied with a 5 pin wire harness. Pin 0 goes to ground, pin 1 at 3.2V, pin 2 at 6.4V, pin 3 at 9.6V and pin 4 12.8V. The last pin is a red positive wire at total pack voltage. Those were the instructions given to me and the parts supplied and usually that is the correct way to do it.

I discovered that the Pin 0 wire (ground) carried load current in parallel to the B- pad because pin 0 and B- are connected within the PCB. I was using a led bulb as the test load so it wasn't a problem. A large load would have smoked that small gauge Pin 0 wire. Cutting the pin 0 wire solved that issue. Now load current has to pass through the correct path and the BMS works as it should.

The better way IMO is to use the three JST 2 pin PH connector sockets that are on the other side of the board and also supply the unique B+ pad with total pack voltage directly from the battery pack. That would be instead of using the supplied 5 pin connector. B- is ground, the first JST 2 pin PH connector would be 3.2V, 2nd is 6.4V, 3rd is 9.6V and the B+ pad is 12.8V. Each 2 pin connector is really 1 connector as the pins are joined within the PCB. 2 pin connector #1, 2 & 3 connect directly to pin #1, 2 & 3 at the previously mentioned 5 pin connector. Pin 5 from the 5 pin connector connects directly to the B+ pad.

I think it is better electrically because, in addition to not paralleling load and charging current from the B- pad on the tiny pin 0 ground wire, the balancing wire capacity is at least doubled by using the 2 pin connectors. I ordered some JST 2 pin harnesses and will do it this way.

The important thing IMO is to not use pin 0 of the 5 pin connector on this particular BMS as it will carry load and charging current in parallel to the correct path. I think the 5 pin connector on this BMS was likely intended to be used only for testing and programming.
I recently came across a wiring diagram that confirms what I figured out last January and am posting it for anyone that has the 150A JBD Smart BMS. Note that Pin 0 is not used in the wiring diagram. I did not use Pin 0 on the Packs I built.

Attached diagram:
alternate bms wiring.jpg

Edit: just adding that I saw a photo of this BMS on another forum but it was labeled Version 1.2 - all three BMS boards I have are Version 1.3
------------
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Old 11-17-2020, 05:20 PM   #269
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Just another app update note. If interested in Xiaoxiang app version 3.1.1020.24 - https://www.classbforum.com/forums/f...tml#post114295 - but couldn't get it to work like me then you could check out Xiaoxiang app version 3.1.1021.25 from - https://www.lithiumbatterypcb.com/sm...ware-download/ - named Smart BMS APP 3.1.1021.2.rar for download.

The application name is 小象电动 so I had trouble finding it on my phone. On my phone it shows up named "Version:"

xiaoxiang 3.1.1021.25 1.png

xiaoxiang 3.1.1021.25 2.png

Works great so far for me. There's more info on the Dashboard and appears to let you turn off charging and discharge independently.
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Old 12-06-2020, 02:29 PM   #270
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A few notes combined in one post to minimize topic bump ups. Log in to see images in this post.

Apps - of the 6+ different apps (apps, not versions of apps) available to use with the battery packs, my preference is the Carplounge app. #1. It comes from Google Play & #2. Pack voltage display resolution is to 10mV on the Dashboard. I really need to see that extra digit to understand where the pack is at relative to reported SOC. Cell voltages are shown to 1mV but not easy to sum on the fly.

JBD released a new version of their app on jiabaida.com. It's xiaoxiang 3.1.1026.27.apk - works's as expected on my phones. It looks very much like version 3.1.1021.25. Probably some improvements.

------------------

Viewing pack info - There's the PC app through USB & Bluetooth for Android & iPhones and also a small LCD display option. I've ordered the LCD to try. I don't know if it's needed or not but at around USD$23 I didn't think too much about getting it. I could have these batteries for 10 or possibly 15 years and the display might be ideal for some future use.

Display will be in English. Pack voltage might be only shown to tenths of a volt. I was asked how many cells in series when I ordered it from ShawnBest Store on AliExpress - https://www.aliexpress.com/item/1005001441224519.html There's more info about it on IC GOGOGO also - https://www.aliexpress.com/item/32878566013.html

JBD BMS LCD.jpg

lcd.jpg

------------------

SOC accumulated error fix - Really small currents, measuring accuracy errors, calibration errors, repeated partial state of charge cycling can all effect the accuracy of the reported coulomb counted SOC. With lead acid batteries there's a requirement to fully charge the battery for performance and longevity. Fully charging the battery resets the SOC measuring device so errors don't accumulate. There's no requirement to fully charge lithium batteries often so the errors can accumulate. JBD BMS let you set 20%, 40%, 60%, 80% & Full voltage set-points. Full is when the reset to 100% SOC occurs. If the error accumulation has grown to where it's noticeable then resetting the pack's capacity is a quick way to force a SOC reset to be within the voltage check points you entered. Access to Reset Capacity feature is through Function Setting in the main menu. If you are cycling the battery and recharging to full frequently then SOC errors won't be noticeable.

Reset Capacity.jpg

---------------

Bluetooth - BT range was not as good as I'd expected so a took a chance and ordered new Bluetooth modules from JBD on AliExpress - https://www.aliexpress.com/store/1379203 . The original BT modules were the color blue with no visible brand and the new modules are green and branded JBD. What a big difference! Range is substantially increased. I have an old Samsung phone that I hoped to use with the packs. It never worked. It would lock the modules in a busy state and require physically unplugging the modules to recover. I tried every app with that phone and none worked. The new BT modules solved that problem too! All of my phones, new and old, work as expected now.

Bluetooth JBD.JPG

BT signal strength 1.jpg
------- ------ ---
BT signal strength 2.jpg

I added JBD to the new BT module names for easy identification. The original module has BMS in the name. You can easily see the difference in signal strength from different areas of my house with all three packs in the same location.

-----------------------

The Packs proved their usefulness during a recent 30 hour grid power outage. I used them to power a kettle & coffee maker in the early AM. I ran a generator during the day and used the Packs to power one fridge and two freezers overnight.
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Old 01-04-2021, 05:59 PM   #271
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Photos of the LCD display mentioned in the previous post (connected to Pack 3):

1.JPG

2.JPG

3.JPG

4.JPG

5.JPG

6.JPG

7.JPG
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